Means for grinding cutlery and oth er articles



(No Model.)

' A. JOHNSTON. MEANs FOR GRINDING GUTLERY OR OTHER ARTICLES. No.465,376. Patented Dec 15, 1891.

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UNITED STATES P TENT OFFI E.

ALLEN JOHNSTON, OF OTTUMWVA, IOW'A.

MEANS FOR GRINDING CUTLERYAND OTHER ARTICLES.

SPECIFICATION forming part of Letters Patent No. 465,376, dated December15, 1891.

Original application filed June 13, 1888, Serial No. 276,947. Dividedand this application filed January 6, 1891. Serial No.

376,902. (No model.)

To all whom it may concern:

Be it known that I, ALLEN JOHNSTON, a citizen of the United States,residing at Ottumwa, in the county of Wapelloand State of Iowa, haveinvented a new and useful Improvement in Means for Grinding Cutlery andother Articles, which improvement is fully set forth in the followingspecification.

The present invention has reference to means for grinding cutlery andother articles made of tempered steel, such as knives, mandrels,spindles, dies, dvc. Thesaid means that are described and claimed hereinare the same as described in my original application Serial No. 276,947,filed June 13, 1888, of which the present is a division andcontinuation. In the manufacture of such articles attempt has frequentlybeen made to utilize emery grinders in place of the ordinarygrindstones; but up to this time the emery grinders have to a limitedextent only superseded the old grindstones, and have no especialadvantage over the latter for the purpose specified.

WVith the object of improving the operation of grinding, particularlywhen emery-Wheels of ordinary compositionare used, I have devisedheretofore a hollow or cup shaped grinder, provided with means forsupplying water to the interior thereof, so that the centrifugal actionof the revolving stone would carry a thin film of Water between thegrinding-surface and the article being ground thereon. Such device isdescribed in my patent, No. 377,201, dated J anuary 31, 1888. Thisstream of water served to conduct away the heat generated by thefriction of the parts in contact and tended to the accomplishment of thedesired object. There still remained, however, serious difficultieswhich render the grinding of cutlery and other like articles a costlyoperation, and with the object of removing these I have undertaken along investigation of the action of ordinary grinders and thedifficulties arising in their use. The emery-wheels most favored bymanufacturers are those compounded by means of vitreous material andknown as vitrified wheels. In observing the action of these Wheels it isnoticed that after a short period of use small particles of steel becomefirmly attached to the grinding-surface and project so far from the facethereof that the knife-blade rides on the top of these particles,instead of coming in contact with the abrading material. In continuingto use such a-grinder the friction of the steel blade and steelparticles causes in tense heat, which has two detrimental effects.First, it causes more steel particlesto become Welded by heat to thosealready adhering to t the grinder, rendering the latter worthlesswithout tedious and costly redressing, and, secondly, it draws thetemper from the blade. This difficulty is intensified when an automaticfeed is employed, for, since the Wheel ceases to grind and the feedkeeps on increasing the pressure, the heating and consequent damage tothe blade and grinder are proportionally increased. Furthermore, ingrinding lathe-spindles, mandrels, and similar articles that are to runin journal-boxes in whicha perfectly smooth surface is a de-,

turning-lathe out of true-that is, with more' metal on one side than onthe other-heat willbe generated on that side which requires to have themost metal removed, causing it to expand toward the grinding-wheel andto bend by reason of such expansion. The grinding being continued, thewheel removes from the heated and expanded side more than the desiredamount of metal, so that when the mandrel cools and contracts, bendingback to the original position, it will still be untrue. Further grindingto correct this difficulty merely transfers the excessive removal ofmetal to the other side of the mandrel, rendering it very difficult toproduce mandrels that are perfectly round and true. It should also bestated that the cost of commercial emery-wheels is extremely high,considering the cheapness of the materials composing it, being abouteight times the cost of such materials. The explanation of this is foundin the fact that the process of manufacture is very uncertain, and thata large proportion of the wheels made are broken or from various defectsare found to be unfi't for use and sale. After much experimentl havebeen able to remove these difficulties completely bymeans of the presentinvention, which consists in the use of a hollow or cupshapedgrinding-wheel, in which the abradin g particles are compacted by abinding material which will melt before a temperature is reachedsufficient to draw the temper, the wheel being capable of containingwater and of spreading it by centrifugal action over thegrinding-surface.

By means of this invention the following results are obtained first,production of a greater amount of work in a given time, asillustrated bythe fact that a knife-blade can be completely ground from an ordinarysteel blank by two movements (one for each side of the knife) back andforth across the grindings urface; second, uniform and superior product,the temper not being in the least degree impaired; third, economy in thegrindin'g-wheels, there being no adherence of steel particles and nonecessity for redressing; fourth, further economy due to the fact thatwheels made as herein described are far cheaper in construction thanvitrified or vulcanite wheels, are not likely to be spoiled in making,and when made will last somewhat longer than vitrified wheels; fifth,the production of perfectly smooth and true cylindrical articles, due Ito the fact that the article is ground always with a clean wheel, andthat before any injurious heat sufficient to produce the effects abovepointed outcan develop, the binding agent would soften and disintegrate.In connection with the employment of a wheel of this kind, the use ofwater in abundance is -of the most importance, not merely to keep thegrinding-surface clean and remove detached particles, but to prevent theheating of the wheel to such extent as to soften and render it unfit foruse, as would otherwise 'very quickly occur.

The composition of materials which I ordinarily prefer to use to makethe emery-wheel consists of nine parts, by weight, of pulverized emeryand one part of shellac, which are heated to or above the melting-pointof the shellac and thoroughly mixed together and then pressed into asuitable mold to form the shape of wheel desired. When col(l,theemery-wheel will be ready for use, and it will melt, soften, ordisintegrate before it will heat the knife or article being ground hotenough to draw its temper. The melting or disintegration of which Ispeak of course takes place only at the surface of the wheel directly incontact with the heated knife, and this emery-wheel will wear awaysmooth the same as any other emery-wheel.

Another formula which I sometimes use is: by weight, sixteen parts ofpulverized emery, two parts of shellac, and one part of plasterof-paris,all heated hot enough'to melt the shellac, thoroughly mixed and pressedinto molds. This makes a somewhat harder wheel than the former and isbetter for some purposes. The shellac may also be cut with alcohol,thoroughly mixed with the emery, and then poured into molds and allowedto remain until dry; but this consumes more time.

There are of course various other materials than shellac known to thoseskilled in the art which will hold the emery together when cold and willmelt or soften and permit the emery again to disintegrate before it willheat the article ground thereon sufficiently to draw its temper, andamong such materials suitable to use I may mention, 'for the sake ofillustration, brimstone and also the various gums similar in nature toshellac.

In the accompanying drawings, which form a part of this specification, Ihave shown at Figure 1 a sectional view of a machine suitable for thepurposes of the invention and in Fig. 2 a perspective view of a hollowemerywheel.

In said drawings, A represents the frame of the machine; B, the hollowemery-wheel; B, its revolving holder, and O the water through which theemery-wheel revolves. C is the elevated compartment of the Water-trough,into which the water or other liquid--oil, for example-is constantlyelevated or delivered by the centrifugal action of the revolvingemery-wheel and its holder, and C is the spout leading from this uppercompartment and by which the water or other cooling-liquid is constantlydelivered upon the inner periphery of the revolving cup-shaped grinderB,so that the centrifugal action thereof will fiow or spread the liquidconstantly over the beveledge grinding-surface of the hollow emerywheelat the place where the grinding is being done. D is the knife or workholder by which the article being ground is automatically reciprocatedin and out of the hollow grinder over and parallel to its inside conicalend surface and held or pressed against such grinding-surface during thegrinding operation. The construction and operation of these parts arefully shown and described in my said former patent, No. 377,201, towhich reference is hereby made, and need not therefore be here againdescribed more particularly than I have done above, as my presentimprovement is independent of the particular construction ofgrinding-machine which may be employed.

The hollow cylindrical emery-wheel B is of such composition of materialsas that it will melt, soften, or disintegrate before the article beingground is heated hot enough by the abrasion to draw the temper of thesteel, so

that the article being ground may be fed across and pressed against theinternal conifrom an article that already has a tolerably smooth surfacethe use of a very fine emery, such as that known commercially as No.180, or even flour-emery would be used in making the emery-wheel, andinstead of Water oil would be used during the grinding operation to cooland clean the surface of the article being ground. If, on the otherhand, the surface is rougher, as is the case with a knife as it comesfrom the forge, it would be necessary to use an emery-wheel made ofcoarser emery first and water to cool and clean the article beingground, and afterward the ing operation.

fine wheel and water are used to finish or polish the surface to therequired fineness.

In case a mandrel or other round article of iron, steel, or other metalis to be ground upon a hollow or cup-shaped em cry-wheel the articlewill of course be made to revolve while being ground.

In grinding shafts, spindles, or mandrels or ends thereof that revolvein journal-boxes the article may be held against the internal inclinededge of the wheel in a position anal0 gous to that shown for the knifein Fig. 2, said article being also revolved during the grind- The lengthand diameter of shaped grinder composed of an abrading substance and abinding agent which fuses or disintegrates under a less heat than willdraw the temper of steel, combined with means for supplying water to theinterior of said wheel, substantially as and for the purposes set'forth.In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

ALLEN JOHNSTON. Witnesses: I

J. T. 'HACKWORTH,

A. G. HARROW.

